Sieve



Nov. 28, 1939. Q B ARNOLD 21,181,718

SIEVE Filed March 19, 1938 F'Q' v @Z Patented Nov. 28, 1939 UNETED STATES PATENT orrlcs SIEVE of Delaware Application March 19,

2 Claims.

This invention relates to a sieve or riddle designed primarily for heavy work, such as sifting of moulding sand, bakers flour, etc. Such a sieve is commonly abused in service; the materials passing through it may be moist or dry; and it is usually deficient in surviving over an extended period on account of the rigors to which it is subjected, particularly if it be of light weight construction as is most desirable. With a view of better withstanding the ordinary conditions of use, and of providing a strong, light, durable, economical, and easily assembled sieve, the present improvements have been devised.

Referring to the drawing:

Figures l and 2 are top and bottom plan views, respectively, of a sieve embodying this invention;

Fig. 3 is a side elevation thereof; ,l

Fig. 4 is a view in vertical section, taken on line 4-4 of Fig. 3, the scale being enlarged;

Fig. 5 is a detail in section, taken on line 5 of Fig. 4; and

Fig. 6 is a view in perspective of the shell from which the sieve body is formed.

The components of the sieve structure are a cylindrical body A, a hoop B applied exteriorly thereto and depending below the lower edge thereof, a stay C fitted to the inside of the hoop below the body, and a screen D extended across the body in the plane of its lower edge, the screen edges being upturned along the body walls to the inside of the hoop thereupon. The special construction and cooperation of these several components will now be explained.

The body is desirably made of a plywood board which is preformed into a cylindrical shell S (see Fig. 6) with its meeting ends u and U squared for butt engagement. In practice, these ends are separated only slightly, if at all, prior to being joined. In a three-ply construction, as shown, the grains of the outer and inner plies, a and c, respectively, are disposed circumferentially, whereas the grain of the intermediate ply b is opposite thereto, i. e., parallel with the axis of the shell. These several plies may be united and subjected to heat and pressure in the manner disclosed in my Patent No. 2,084,179, dated June l5, 1937, so that when the plywood board is bent into a cylindrical shell its form will remain fixed. A strip of plywood, similarly produced and treated, is desirably utilized for the hoop, whose end portions w and rv, however, may be disposed in an overlapping joint. The stay, which receives less wear and tear than the other components, may consist of a single 1938, Serial No. 196,853

strip with its ends y and z chamfered for a scarfed joint, the strip end .e lying adjacent the hoop end w so as to occupy the space which is inwardly of the other hoop end In assembling the components of the present 5 sieve, the ends of the body shell are first securely joined. This is accomplished with the aid of a metallic strap E having two parallel limbs 'l and 8 connected by a web 9. The length of the limbs is about equal to that of the Shell 10 and the reverse bend forming the web is suiiiciently short to space the two limbs apart a distance which about equals the thickness of the shell wall upon whose surfaces the limbs are extended. The strap, if made of spring metal, l5 may exert l a pressure upon opposite sides of the body so as to fit thereupon in the manner of a resilient clip. The connecting web is adapted to fit closely upon the upper edge of the sieve body, when assembled therewith. At its 20 opposite ends the web may be downturned, obliquely or otherwise, to provide in effect tongues t which will enter the sieve body, when driven thereinto, to secure the shell ends against separation. Accordingly, it will be found advan- 25 tageous, in completing the butt joint at the ends ofA the shell, to first advance these ends (if necessary) into mutual engagement, to then apply the strap to bridge the joint, or, if desired, to first apply the strap and then advance the 30 shell ends into meeting relation, and finally to drive down the web suiciently to cause the tongues to bite into the top edge of the shell.

A temporary locking of the shell ends is thereby afforded. 35

The next step is to assemble the screen, the

hoop and the stay in place. In doing this the screen is placed across the bottom of the body, its edges are upturned to lie over the exterior limb of the strap, and the hoop, with stay afxed 40 thereto, is applied over the screen edges and fitted to the body exterior with its lower portion extending below the screen. An alternative procedure is to set the stay in position to the inside of the hoop below the screen, after the body, 45 screen and hoop have been assembled. With the sieve components so disposed, a stapling operation is now performed, preferably with the aid of a machine such as is regularly available for such purposes. Staples are driven in from the outside, 50 as at l! to interconnect the hoop and stay, as at Il to interconnect the hoop, strap, screen and body, and,.as at l2 to interconnect the strap and body. The overlapping end portions of the hoop and stay are either secured by one or more of the 55 staples I and Il, or by separate nails, according as may be preferred.

In the complete sieve the strap web may be driven down until it is practically flush with the top edge of the body. The strap serves furthermore to maintain the body ends in alignment under all conditions of use. The joint in the bod;7 is leak-proof, or substantially so, by reason of the tight butt engagement between its ends, due (1) to the drawing-together action of the tongues on the top plate of the strap, and (2) to the overlap of the joint by the two limbs of the strap. The exterior of the sleeve is devoid of sharp points, since the clinched ends of the `staples are all disposed to the inside thereof. By `the presence of the stay the screen may be supported up to a point close to the inner surface of the sieve, which dei-mes the opening from and through which sifted material is to be discharged. And nally, by employing plywood boards for the body and hoop, it Akis `possible to preform these parts so that they will Aretain their .circular shape without tension so ,as to afford a Igreater resistance to forces which otherwise might crush or deform the sieve to the point of ruination. The present sieve may, therefore, be lighter in weight Afor the same strength or be made stronger for the same weight-very important considerations in an article of this kind Which in commercial service is handled roughly and often abused unmercifully.

I claim:

1. A sieve comprising a body of plywood having a permanent cylindrical form with its ends aligned for butt joint engagement, a metal strap of materially greater width than said joint applied over one face of the body at the joint to extend from top to bottom thereof, the strap being extended over the top edge of the body and down upon the opposite face to furnish a support for maintaining the body ends in enclosed, abutting alignment, a plywood hoop surrounding the body, and a screen extending across the bottom end of the body with'ts edges upturned to overlie said strap between the body and hoop, tongue means carried by the strap in engagement with the body adjacent its ends acting to prevent sep- ,aration thereof, and staple means extending transversely through the hoop, screen, strap and Y body on each side of said joint, whereby a sieve of minimum weight having maximum strength and durability is provided.

2.v A sieve comprising a cylindrical body of ply- Wood having a butt joint, a sheet metal strap of materially greater width than said joint applied exteriorly upon the body over the joint thereof, a plywood `hoop surrounding the body to extend from top to bottom on both sides of the body to enclose said joint and having voverlapping end portions depending therebelow, a screen extending across the body yadjacent its bottom with the screen edges upturned to lie between the body and hoop and overlie said strap, and a stay portion adjacent the underside of the screen provided by a spiral continuation of the hoop, and the inner end portion of the stay being tapered and overlapping the abutting ends of the hoop and stay portions.

CHARLES B. ARNOLD. 

